Steam-engine expansion-gear.



JfDAVIDSON & W. 0. LARMUTH.

STEAM ENGINE EXPANSION GEAR.

A'PPLIUATION FILED JUNE 5, 1911.

Patented Jan.7, 1913.

COLUMBIA PLANOGRAIH CO.,WASIHNGTON, u c.

STEAM-ENGIN E EXPANSION-GEAR.

Specification of Letters Patent.

Patented Jan. 7,1913.

Application filed June 5, 1911. Serial No. 631,239.

To all whom, it may concern:

Be it known that we, JOHN DAVIDSON and WILLIAM OLIVER LARMUTH, subjects of the King of Great Britain, residing at Pendleton and Salford, respectively, both in the county of Lanicaster, Kingdom of Great Britain, have invented certain new and useful Improvements in Steam-Engine EX- pansion-Gear; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

. valve driving shaft 0.

10op1es of this patent may be obtained for This improvement relates to the class of engines in which the cut off and consequently the degree of expansion. isvaried by altering the travel and angleof advance of the eccentric which drives the valve or valve gear.

The object of our invention is to simplify the mechanism which actuates the eccentric which drives the valves or valve gear by employing a relay motor in combination with a centrifugal governor of any well known type.

Ordinarily crankshaft governors of massive construction are employed to alter the position of the eccentric, but as these require to be of such large dimensions if an ample supply of power to move the eccentric is allowed for, we propose to effect the change in the eccentric by a relay motor which may be actuated by steam, oil, or,

water under pressure, said motor or cylinder being controlled by a small valve which will be coupled to a governor in the well known way. We attain this object by the mechanism illustrated in the accompanying drawing, in which Figure l is a sectional side View of an eccentric relay motor mechanism constructed in accordance with our invention. Figs. 2 and 3 are sectional plans on lines AA and BB of Fig. 1 respectively.

Similar letters refer to 7 similar throughout the several views.

Referring to the drawing, the eccentric a for driving the valve or valve gear is mounted on a smaller eccentric b, which is firmly keyed to or formed with the crankshaft or The center of the eccentric a is a, and the center of eccentric parts five cents each, by Washington, D. 0.

b is 7). To the crank shaft or valve actuating shaft 0, is secured a bracket 03 projecting from each side thereof. In each end of this bracket is mounted a shaft d having secured at oppositeends an arm 6 which is connected to the eccentric a by means of the rods f and To the said shafts are also secured the arms 9 each furnished at its free end with a pin 72. carrying a block 71 adapted to engage in an annular groove in the sleeve 7c on the crank shaft or valve actuating shaft 0. The sleeve 7c is operated by means of a lever Z with fulcrum at m the sleeve carrying a ring a in which it is free to rotate, which is fixed to the lever Z at 0. The end of the lever Z at p is coupled to the relay cylinder piston g, the position of which will be regulated by valve 1" from the governor s in the well known way. l/Vhen the relay cylinder piston g is actuated, the lever Z causes the sleeve to slide along the crank shaft or valve actuating shaft 0 and through the connection 9, e, f, the eccentric a to be circularly displaced on the eccentric b moving in the path a, a

To claim:

In a steam valve actuating gear comprising two eccentrics adjustably mounted upon each other on the valve actuating shaft and a relay cylinder and piston wit-h piston rod I governed by a governor, ,rods pivoted to one of the said eccentrics, arms connected to i the said rods, a bracket mounted on the said shaft, shafts mounted in the said bracket, arms securedto the second named shafts and connected to the said rods, arms mounted on the second named shafts, a sleeve on the first named shaft, two grooves in the said sleeve in one of which engage the sec- 0nd named arms, a ring in the second groove, and a lever fulcrumed at one. end and connected at the other end to the said piston rod, and connected between the said ends to the said ring, substantially for the purpose set forth. a v

In testimony whereof we have aflixed our signatures in presence of two witnesses.

JOHN DAVIDSON. WILLIAM OLIVER LARMUTH. Witnesses: t y

ALFRED BossHARDT, STANLEY E; BRAMALL.

addressing the Commissioner of Patents, 

